Starch and products derived from it are very important products especially in the food industry. For the food industry, starch is commonly converted into different kinds of syrups such as dextrose syrups, fructose syrups, mannose syrups and the like. These can be used as basic carbon sources in processes for the production of other kinds of syrups, which in turn may serve to produce solidified or crystalline products. These processes include catalytic reactions such as isomerisation, epimerisation, hydrogenation. For example, dextrose in dextrose syrup can be enzymatically isomerised into fructose by the action of magnesium as a catalyst. After catalytic reaction, the end product is purified by removal of the catalyst by using ion exchange resins.
One of the problems with current purification methods is that they result in high amounts of waste. In particular, the catalysts removed with the resin regeneration step are discharged as waste streams. This has a negative impact on the environment and on the quality of waste water streams coming from industry. It is not economically interesting to recover the catalysts from the waste streams. The fact that high cost products such as catalysts are lost in waste streams increases the total cost of the process and requires a very controlled dosage of the catalyst which otherwise would be lost if dosed in excess. There is thus currently a necessity to compromise between reaction efficiency and loss of catalyst.
There is thus a need for an improved process for purification of syrups containing charged components, such as catalyst in the form of salts. There is a need for a process having a higher catalyst recovery yield and a lower environmental impact than current purification processes.